<!DOCTYPE html>
<meta charset="UTF-8">
<form action="demo_form.php" method="get" >
  Name1: <input type="text" name="usr_name1" required="required" /><br>
  Name2: <input type="text" name="usr_name2" required="required" pattern="^\\d.*$" formnovalidate /><br>
  Name3: <input type="text" name="usr_name3" required="required" pattern="^\d.*$" placeholder="请输入数字!"/><br>
  <input type="submit" />
</form>

